It has previously been proposed to change the light distribution or light incidence of an illuminated area, particularly of operating-room lights, by providing a fully reflective mirror, in reflective position with respect to a light source and to include, in advance of the fully reflective mirror, a reflector system which has a mirror portion which is partially transmissive and partially reflective. By suitable change of the partially transmissive, partially reflective mirror with respect to the main, or fully reflecting mirror, different distribution of light incident on an illuminated area can be obtained.
British Pat. No. 1,537,181 describes an operating-room light which has a light source from which light beams are directed to two reflectors. The light beams are partially reflected from the first reflector, and partially transmitted; the transmitted portion, then, is directed to a second mirror or reflector. The inclination of the wholly reflecting or main reflecting mirror can be changed with respect to the axis of the originally emitted light beams. The result, as far as the illuminated field is concerned, will be that each one of the mirrors or reflectors will provide separate beam of light; these beams can be individually focussed.
In one such arrangement, eight beams of light are provided, being directed from four different directions on the field to be illuminated. The structure is intended to prevent the formation of heavy shadows. It has been found, however, that the distribution of light, and particularly light which permits illumination of cavities, and provides excellent depth perception, should be improved.